All the information below can be found HERE, though geared towards farmers its a very interesting and helpful read, there is a smaller leaflet and a bee calendar available also.
n order to sustain a wide diversity of pollinators in the countryside it is vitally important to provide a range of flower resources throughout their active period – between March and September.
Starter. Spring (March to end of May). Flowers at this time are vitally important for queen bumblebees founding nests and also early emerging solitary bees. Flowers are often scarce at this time and it can be a challenge to provide them – indeed this might be considered the pollinator ‘hungry gap’. Most wildflowers we see at this time of year are not commercially available as seed, so value what comes for free in hedgerows and headlands and accommodate them whenever possible.
Main course. Mid-summer (June to mid-August). An abundance of flowers is needed to ensure large and productive bumblebee and honeybee colonies, and successful second broods for solitary bees.
Dessert . Late-summer (late August to the end of September). Late season flowers can be easily forgotten. These are important for feeding mated queen bumblebees before Winter to increase their chances of survival to the following year.